Theoretical study of Na excitation and ionization inH++Na collisions

Na excitation and ionization cross sections in ${\mathrm{H}}^{+}$+Na collisions are determined at impact energies 0.7–50 keV within the semiclassical close-coupling method with atomic-orbital basis sets including pseudostates. Calculated Na(3s→3p) excitation cross sections and the 3p alignment show structures which agree very well with available experimental data. While a structure at 3 keV is predominantly caused by interaction between capture and excitation channels, interaction between excitation and ionization channels leads to a shoulder in the calculated 3p excitation cross section at higher energies and a correlated distinct dip in the predicted ionization cross section.